nodeForeignscan.c File Reference

#include "postgres.h"
#include "executor/executor.h"
#include "executor/nodeForeignscan.h"
#include "foreign/fdwapi.h"
#include "utils/rel.h"

Include dependency graph for nodeForeignscan.c:

Go to the source code of this file.

Functions
static TupleTableSlot *	ForeignNext (ForeignScanState *node)
static bool	ForeignRecheck (ForeignScanState *node, TupleTableSlot *slot)
TupleTableSlot *	ExecForeignScan (ForeignScanState *node)
ForeignScanState *	ExecInitForeignScan (ForeignScan *node, EState *estate, int eflags)
void	ExecEndForeignScan (ForeignScanState *node)
void	ExecReScanForeignScan (ForeignScanState *node)

---

Function Documentation

void ExecEndForeignScan

(

ForeignScanState *

node

)

Definition at line 183 of file nodeForeignscan.c.

References FdwRoutine::EndForeignScan, ExecClearTuple(), ExecCloseScanRelation(), ExecFreeExprContext(), ForeignScanState::fdwroutine, ScanState::ps, PlanState::ps_ResultTupleSlot, ForeignScanState::ss, ScanState::ss_currentRelation, and ScanState::ss_ScanTupleSlot.

Referenced by ExecEndNode().

{
    /* Let the FDW shut down */
    node->fdwroutine->EndForeignScan(node);

    /* Free the exprcontext */
    ExecFreeExprContext(&node->ss.ps);

    /* clean out the tuple table */
    ExecClearTuple(node->ss.ps.ps_ResultTupleSlot);
    ExecClearTuple(node->ss.ss_ScanTupleSlot);

    /* close the relation. */
    ExecCloseScanRelation(node->ss.ss_currentRelation);
}

TupleTableSlot* ExecForeignScan

(

ForeignScanState *

node

)

Definition at line 89 of file nodeForeignscan.c.

References ExecScan(), ForeignNext(), and ForeignRecheck().

Referenced by ExecProcNode().

{
    return ExecScan((ScanState *) node,
                    (ExecScanAccessMtd) ForeignNext,
                    (ExecScanRecheckMtd) ForeignRecheck);
}

ForeignScanState* ExecInitForeignScan	(	ForeignScan *	node,
		EState *	estate,
		int	eflags
	)

Definition at line 102 of file nodeForeignscan.c.

References Assert, FdwRoutine::BeginForeignScan, EXEC_FLAG_BACKWARD, EXEC_FLAG_MARK, ExecAssignExprContext(), ExecAssignResultTypeFromTL(), ExecAssignScanProjectionInfo(), ExecAssignScanType(), ExecInitExpr(), ExecInitResultTupleSlot(), ExecInitScanTupleSlot(), ExecOpenScanRelation(), ForeignScanState::fdw_state, ForeignScanState::fdwroutine, GetFdwRoutineForRelation(), makeNode, Scan::plan, PlanState::plan, ScanState::ps, PlanState::ps_TupFromTlist, Plan::qual, PlanState::qual, RelationGetDescr, ForeignScan::scan, Scan::scanrelid, ForeignScanState::ss, ScanState::ss_currentRelation, PlanState::state, Plan::targetlist, and PlanState::targetlist.

Referenced by ExecInitNode().

{
    ForeignScanState *scanstate;
    Relation    currentRelation;
    FdwRoutine *fdwroutine;

    /* check for unsupported flags */
    Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));

    /*
     * create state structure
     */
    scanstate = makeNode(ForeignScanState);
    scanstate->ss.ps.plan = (Plan *) node;
    scanstate->ss.ps.state = estate;

    /*
     * Miscellaneous initialization
     *
     * create expression context for node
     */
    ExecAssignExprContext(estate, &scanstate->ss.ps);

    scanstate->ss.ps.ps_TupFromTlist = false;

    /*
     * initialize child expressions
     */
    scanstate->ss.ps.targetlist = (List *)
        ExecInitExpr((Expr *) node->scan.plan.targetlist,
                     (PlanState *) scanstate);
    scanstate->ss.ps.qual = (List *)
        ExecInitExpr((Expr *) node->scan.plan.qual,
                     (PlanState *) scanstate);

    /*
     * tuple table initialization
     */
    ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
    ExecInitScanTupleSlot(estate, &scanstate->ss);

    /*
     * open the base relation and acquire appropriate lock on it.
     */
    currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid, eflags);
    scanstate->ss.ss_currentRelation = currentRelation;

    /*
     * get the scan type from the relation descriptor.  (XXX at some point we
     * might want to let the FDW editorialize on the scan tupdesc.)
     */
    ExecAssignScanType(&scanstate->ss, RelationGetDescr(currentRelation));

    /*
     * Initialize result tuple type and projection info.
     */
    ExecAssignResultTypeFromTL(&scanstate->ss.ps);
    ExecAssignScanProjectionInfo(&scanstate->ss);

    /*
     * Acquire function pointers from the FDW's handler, and init fdw_state.
     */
    fdwroutine = GetFdwRoutineForRelation(currentRelation, true);
    scanstate->fdwroutine = fdwroutine;
    scanstate->fdw_state = NULL;

    /*
     * Tell the FDW to initiate the scan.
     */
    fdwroutine->BeginForeignScan(scanstate, eflags);

    return scanstate;
}

void ExecReScanForeignScan

(

ForeignScanState *

node

)

Definition at line 206 of file nodeForeignscan.c.

References ExecScanReScan(), ForeignScanState::fdwroutine, FdwRoutine::ReScanForeignScan, and ForeignScanState::ss.

Referenced by ExecReScan().

{
    node->fdwroutine->ReScanForeignScan(node);

    ExecScanReScan(&node->ss);
}

static TupleTableSlot * ForeignNext

(

ForeignScanState *

node

)

[static]

Definition at line 41 of file nodeForeignscan.c.

References ExecMaterializeSlot(), ForeignScanState::fdwroutine, ForeignScan::fsSystemCol, FdwRoutine::IterateForeignScan, MemoryContextSwitchTo(), PlanState::plan, ScanState::ps, PlanState::ps_ExprContext, RelationGetRelid, ForeignScanState::ss, ScanState::ss_currentRelation, HeapTupleData::t_tableOid, and TupIsNull.

Referenced by ExecForeignScan().

{
    TupleTableSlot *slot;
    ForeignScan *plan = (ForeignScan *) node->ss.ps.plan;
    ExprContext *econtext = node->ss.ps.ps_ExprContext;
    MemoryContext oldcontext;

    /* Call the Iterate function in short-lived context */
    oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
    slot = node->fdwroutine->IterateForeignScan(node);
    MemoryContextSwitchTo(oldcontext);

    /*
     * If any system columns are requested, we have to force the tuple into
     * physical-tuple form to avoid "cannot extract system attribute from
     * virtual tuple" errors later.  We also insert a valid value for
     * tableoid, which is the only actually-useful system column.
     */
    if (plan->fsSystemCol && !TupIsNull(slot))
    {
        HeapTuple   tup = ExecMaterializeSlot(slot);

        tup->t_tableOid = RelationGetRelid(node->ss.ss_currentRelation);
    }

    return slot;
}

static bool ForeignRecheck	(	ForeignScanState *	node,
		TupleTableSlot *	slot
	)			[static]

Definition at line 73 of file nodeForeignscan.c.

Referenced by ExecForeignScan().

{
    /* There are no access-method-specific conditions to recheck. */
    return true;
}